Conventionally, there has been a problem in a programmable logic controller that it takes time to perform troubleshooting in a case where a malfunction of a sequential function chart (SFC) program has been caused by an incorrect operation of a device value.
Patent Literature 1 discloses a programmable logic controller in which an SFC program and an output state of a device in the SFC program can be confirmed on a single screen for easy troubleshooting.